1. Field of the Invention
The present invention relates to an ink cartridge with a closing device for ink jet printers or similar writing, printing or drawing units, wherein the ink cartridge in the printer as well as the closing device are releasably mounted on the ink cartridge, wherein the ink cartridge can be filled manually or automatically with ink from an external tank, wherein the ink cartridge includes at least one housing, an ink reservoir and a refill opening, and wherein the refill opening is closeable by the closing device.
2. Description of the Related Art
Closeable ink cartridges of the above-described type are connected permanently or exchangeably to a printer head and/or to a printer and are either manually refillable as necessary or are continuously supplied with ink, for example, through a hose system, from a larger external tank. However, in principle, disposable cartridges may also be used or modified.
The ink cartridges of this type are used in ink jet systems which include all usually electronically controlled automatic writing, drawing and printing units or devices which use preferably so called ink jet heads for producing writing or illustrations and whose ink storage units are usually releasably mounted and connected to the printer head directly or indirectly through an ink supply system, wherein the writing or drawing medium is particularly ink and the discharge elements are printer heads with jets as outlet openings in different arrangements and sizes.
These printers, which usually can be filled or refilled through exchangeable ink cartridge and/or also through hose supply systems, sometimes also operate with modified cartridges which can be exchangeably placed into the respective printer head or which are permanently connected to the printer head and are then mounted completely as a unit in the printer.
In that case, the ink cartridges may be modified to the extent that they have on there housing a coupling element, such as, for example, a connecting pipe piece, which is constructed for making it possible to easily refill the cartridge or to connect a hose system which is in communication with a large ink tank and is possibly provided with a closing device.
The volume of the ink tank may be a multiple of the filling volume of a commercially available filled ink cartridge for ink jet printers.
The connecting pipe piece may also be used for manually filling the cartridge and is usually closed in an air-tight manner with a closing cap.
Various solutions for ink cartridges and systems of this type are known in the art.
For example, DE 196 15 997 A1 discloses a manually refillable ink cartridge with an ink tank for free ink and a compensating and regulating system, and with a refill opening which during use in the system is closed in an air-tight manner with a closing cap.
DE 296 03 466 U1 and U.S. Pat. No. 5,329,294 disclose devices for manually refiling ink cartridges, wherein after filling the filling opening is once again closed in an air-tight manner with an elastomer plug or with an adhesive strip.
A particular disadvantage of the known systems is the fact that the ink contained in the ink cartridge does not last very long particularly when printing large surface areas, and that the respective ink cartridge has to be frequently exchanged or refilled as a result. In addition, these cartridges require storage filters and/or other usually complicated buffer elements or compensating systems for ensuring a regulated discharge of the ink through the printer head and for preventing the undesired discharge of ink, for example, in the case of pressure increases in the system or when air enters in an uncontrolled manner.
These ink cartridges or printer heads with ink reservoirs cannot be refilled through a tank/hose system, but are to be exclusively manually filled with a refill bottle or with an injection device.
Consequently, ink cartridges have already been modified in practice in such a way that the filling opening was provided with a hose connection through which a continuous ink supply from a large additional tank and simultaneously also a controlled discharge of the ink were made possible. The connected hose or the hose system and the supply control usually also serve as a pressure compensating element which acts by regulating the ink flow from the printer head or the jet plate through negative pressure and prevents ink from being discharged during non-use.
The filling opening or the hose connection are usually sealed in an air-tight manner with a releasable closing cap when the cartridge is transported or stored.
Such printer heads or cartridges have the disadvantage that, when the hose system is not connected and when no buffer system is present, the ink contained in the cartridge or the printer head can run out almost entirely unimpededly when the closing opening is not closed air-tight, or the flow of ink is interrupted quickly when sufficient air is prevented from entering the cartridge. Consequently, such cartridges or printer heads cannot be used for short periods of time for testing purposes and they cannot be safely used under normal operating conditions.
Another disadvantage of central supply systems with hose connections is the fact that a change of the type of ink, for example, from textile inks or pigment inks or black inks to color inks or the like, or also a short "intermediate test" with other media, can only be carried out with a complicated and expensive complete cleaning of the entire system and, thus, was not possible in the past without problems.